﻿ Getting Started Tutorials - MechDesigner > Tutorial 5: Kinematic Function Blocks for Motion > Step 5.7: The Point-Data FB and Measurement FB

# Step 5.7: The Point-Data FB and Measurement FB

## Point-Data FB and Measurement Function-Blocks

The Point-Data FB and the Measurement FB have output-connectors only.

We will use a:

Point-Data FB to measure the position and motion of a Point*, relative to the origin of the Base-Part.

Measurement FB to measure the motion of one sketch-element relative to another - usually in different Parts.

The motion-values at their output-connectors of these FB provide the measurements AND also their first and second motion-derivatives.

* In all cases below, we the term Point, to mean Point, start-Point, end-Point, center-Point, and Motion-Point.

### Motion-Dependency

Motion-Dependency is an important and useful concept.

Motion-Dependency is a term we use when the motion of a kinematic-chain is a function of the motion of a different kinematic-chain.

In two examples below (5.7-B and 5.7-C) there are TWO kinematic-chains.

Kinematic-chain A : here a Crank. A wire from a Linear-Motion FB  is connected to the input of a Motion-Dimension FB.

We measure, with a Measurement FB, the distance from a stationary Point in the Base-Part to the end-Point of the Crank. The distance continually changes as we cycle the model.

The output from the Measurement FB provides not only the distance between the two Points, but also the first and second motion-derivatives of the distance between the two Points.

Kinematic-chain B: here a Slider. It takes the motion-values at the output from the Measurement FB as its motion and input to the Motion-Dimension FB, for the Slider.

 5.7-A: Plot Motion-Values of a Point with a Point-Data FB and a Graph FB
 5.7-B: Motion-Dependency 1: Kinematic-Chain A provides motion-value to Kinematic-Chain B
 5.7-C: Motion-Dependency 2: Kinematic-Chain A provides motion-value to Kinematic-Chain B
 Develop a Stationary Cam